Detection of locally radio-recurrent prostate cancer at multiparametric MRI: Can dynamic contrast-enhanced imaging be omitted?

Objective: The goal of this study was to assess the added value of dynamic contrast-enhanced (DCE) imaging in detecting locally radio-recurrent prostate cancer using multiparametric magnetic resonance imaging (mpMRI) at 3 Tesla (T). Materials and methods: We retrospectively analyzed 45 patients with rising prostate-specific antigen level after prostate radiotherapy who underwent mpMRI [T2-weighted (T2w), diffusion-weighted (Dw) and DCE imaging] at 3 T before prostate biopsy. Four readers assigned a 5-level Likert score of cancer likelihood in 8 prostate sectors (6 sextants, 2 seminal vesicles) on T2w + Dw and T2w + Dw + DCE images. Biopsy results were used as the standard of reference. Results: T2w + Dw and T2w + Dw + DCE imaging had similar areas under the receiver operating characteristic curves on per-sector (0.87-0.89 vs. 0.87-0.89; P = 0.19-0.78) and per-lobe (0.82-0.94 vs. 0.80-0.91; P = 0.21-0.84) analysis. Using a Likert score = 2/5 for diagnosis threshold, T2w + Dw + DCE imaging showed non-significantly higher sensitivities on per-sector (0.56-0.72 vs. 0.52-0.73, P = 0.34-0.69) and per-lobe (0.80-0.90 vs. 0.73-0.88; P = 0.63-0.99) analysis. It also showed non-significantly lower specificities on per-sector (0.74-0.89 vs. 0.82-0.89; P = 0.09-0.99) and per-lobe (0.48-0.81 vs. 0.61-0.84; P = 0.10-0.99) analysis. Weighted kappa values were respectively 0.57-0.70 and 0.55-0.66 for T2w + Dw and T2w + Dw + DCE imaging at the sector level, and 0.66-0.83 and 0.58-0.85 at the lobe level. Conclusion: The use of DCE MR imaging tends to increase sensitivity and decrease specificity for all readers, but the differences are not significant. (C) 2016 Published by Elsevier Masson SAS on behalf of the Editions francaises de radiologie.